R. Mauersberger and C. Henkel
Dense gas in nearby galaxies. IV - The detection of N<sub>2</sub>H<sup>+</sup>, SiO, H<sup>13</sup>CO<sup>+</sup>, H<sup>13</sup>CN, and HN<sup>13</sup>C,
Astron. Astrophys. 245, 457-466 (1991).
Source(s): NGC253, Maffei 2, IC342, M82, NGC6946
Facility: IRAM 30m
Contributor(s): S. Thorwirth; 09/2005